Astrometry Archives

Scientists have found thousands of exoplanets (planets outside our solar system) throughout the galaxy. Most can be studied only indirectly, but scientists know they vary widely, as depicted in this artist’s concept, from small, rocky worlds and gas giants to water-rich planets and those as hot as stars. Credit: NASA’s Goddard Space Flight Center Larger image

NASA’s Exoplanet Discovery Exceeds 6,000 Worlds

by Keith CowingSeptember 17, 2025September 17, 2025

The official number of exoplanets — planets outside our solar system — tracked by NASA has reached 6,000. Confirmed planets are added to the count on a rolling basis by […]

Stellar Cartography tracking session - Paramount/Astrobiology.com

Away Teams & Field Reports, Budgets and Policy, Imaging & Spectroscopy, Interstellar, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Policy, Status Report, Stellar Cartography

Stellar Cartography: A Demonstration Of Interstellar Navigation Using New Horizons

by Keith CowingJuly 1, 2025July 1, 2025

Editor’s note: Those of you in the space community know that NASA Science is facing an immense budget cut. Dozens of missions have been cancelled and many missions that are […]

The colour-magnitude diagram of the CPM companion stars to host stars of confirmed exoplanets (left) and TOI PCs (right), corrected for G band extinction. The background consists of the primary and secondary stars in the El-Badry et al. (2021) binary catalog. The companion sources below the main sequence are discussed in Section 6.1. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report

A High Stellar Multiplicity Rate Amongst TESS Planet Candidates In The Neptunian Desert Using Gaia DR3 Astrometry

by Keith CowingJuly 1, 2025July 1, 2025

We aim to discover whether the stellar multiplicity rate may provide information on the origin of recently discovered planets in the Neptunian Desert.

Heatmaps of the NEID Solar RV measurements over time. The x-axis represents the 330 days with measurements (in order, but not scaled by time). The black vertical line is at the day when the detector was shut off due to a forest fire and subsequently brought back online. The top subplot displays the unadjusted distribution of RVs for each line (note that around 4% of the observations fall outside the limits of this plot). The bottom subplot displays the RVs that have been centered by line and by the temporal group (note that around 2% of the observations fall outside the limits of this plot). The colors indicate the number of RV measurements from absorption lines within each bin (orange = fewer lines, blue = more lines). Bins are vertical so that there is no overlap between days. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

Searching for Low-Mass Exoplanets Amid Stellar Variability with a Fixed Effects Linear Model of Line-by-Line Shape Changes

by Keith CowingFebruary 18, 2025

The radial velocity (RV) method, also known as Doppler spectroscopy, is a powerful technique for exoplanet discovery and characterization. In recent years, progress has been made thanks to the improvements […]

GP model fit to the RV data. Left panel shows the entire RV time series in black and the GP model in blue, with residuals plotted in the lower panel, to demonstrate that a quasiperiodic GP model was able to capture the long-period variation caused by the stellar magnetic cycle. The gray shaded region is shown in the right panel. The right panel shows the same model and data over a centrally located 60 day baseline, to highlight the effects of the 9.42 day stellar rotation period. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

The Magnetically Induced Radial Velocity Variation of Gliese 341 and an Upper Limit to the Mass of Its Transiting Earth-sized Planet

by Keith CowingFebruary 13, 2025February 13, 2025

The Transiting Exoplanet Survey Satellite (TESS) mission identified a potential 0.88 REarth planet with a period of 7.577 days, orbiting the nearby M1V star GJ 341 (TOI 741.01).

Gaia-4b is a planet orbiting the star called Gaia-4, around 244 light-years away. Gaia-4b is about twelve times more massive than Jupiter. With an orbital period of 570 days, it is a relatively cold gas giant planet. Gaia-5b is a brown dwarf orbiting the star Gaia-5, around 134 light-years away from Earth. With a mass of around 21 Jupiters, Gaia-5b is more massive than a planet but too light to sustain the nuclear fusion necessary to be a star. This artist impression visualises a portion of both objects’ orbital motions as determined by Gaia’s astrometric data. The stars and planets are not to scale. -- ESA/Gaia/DPAC/M. Marcussen

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gaia Mission, Imaging & Spectroscopy, Press Release

High-precision NEID Spectrograph Helps Confirm First Gaia Astrometric Planet Discovery

by Keith CowingFebruary 5, 2025February 5, 2025

NEID (rhymes with fluid) is a high-precision radial-velocity spectrograph that is designed to measure the extremely minute wobble of nearby stars using the radial velocity effect. This effect results from […]

Determining a planetary mass - Grok via Astrobiology.com

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Effects of Planetary Mass Uncertainties on the Interpretation of the Reflectance Spectra of Earth-like Exoplanets

by Keith CowingFebruary 4, 2025

Atmospheric characterization of Earth-like exoplanets through reflected light spectroscopy is a key goal for upcoming direct imaging missions. A critical challenge in this endeavor is the accurate determination of planetary […]

General illustration of the calibration of the distortion. The reference stars are used to adjust a bivariate polynom T that relates the positions of the detector plane to the sky positions. The motion of the target is observed using this transformation. -- astro-ph.IM

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

Experimental Tests Of The Calibration of High Precision Differential Astrometry for Exoplanets

by Keith CowingDecember 29, 2024December 28, 2024

High precision differential Astrometry is the branch of astronomy that evaluates the relative position, distance and motion of celestial objects with respect to the stars present in the field of […]

A comparison between the seven longest period (if fully confirmed at current values) candidates from this paper, and the KOI catalog (Thompson et al. 2018). Equilibrium temperatures and apparent magnitudes are taken directly from the respective TOI and KOI catalogs. Note that TOI1894’s period could be half what is reported. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Validating the Orbital Periods of the Coolest TESS Exoplanet Candidates

by Keith CowingNovember 27, 2024May 22, 2025

When an exoplanet passes in front of its host star, the resulting eclipse causes an observable decrease in stellar flux, and when multiple such transits are detected, the orbital period […]

Schematic view of the seven planetary systems studied in this work. In the upper panel, the location on the x-axis shows the orbital semi-major axis of the planets in question, on a linear scale, with the horizontal lines reaching out from the planet showing the range of its orbit from pericentre to apocentre. The size of the marker for each planet gives the observed radius, as presented in the discovery work, whilst the colour of the marker gives the measured mass for the planet. In the case of the planets orbiting HD 63433, no measured mass has been obtained to date, and we therefore plot an estimated mass for the two planets in that system, based on Figure 3 of Chen & Kipping (2017). In the case of TOI 1670 b, the mass given is an upper limit. The lower panel presents most of the same information (mass, radius, etc.), but shows the separation of the planetary systems in terms of their orbital periods, with the period of the inner planet in each system set to unity. The parent stars are shown sized relative to one another, but not to scale with their planets, and their colour in the plot denotes their effective temperatures, Teff. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The Search For The Inbetweeners: How Packed Are TESS Planetary Systems?

by Keith CowingNovember 7, 2024November 7, 2024

In this work, we examine seven systems discovered by TESS, to see whether there is any room in those systems for an additional planet (or several) to lurk unseen between […]

Astrometry

NASA’s Exoplanet Discovery Exceeds 6,000 Worlds

Stellar Cartography: A Demonstration Of Interstellar Navigation Using New Horizons

A High Stellar Multiplicity Rate Amongst TESS Planet Candidates In The Neptunian Desert Using Gaia DR3 Astrometry

Searching for Low-Mass Exoplanets Amid Stellar Variability with a Fixed Effects Linear Model of Line-by-Line Shape Changes

The Magnetically Induced Radial Velocity Variation of Gliese 341 and an Upper Limit to the Mass of Its Transiting Earth-sized Planet

High-precision NEID Spectrograph Helps Confirm First Gaia Astrometric Planet Discovery

Effects of Planetary Mass Uncertainties on the Interpretation of the Reflectance Spectra of Earth-like Exoplanets

Experimental Tests Of The Calibration of High Precision Differential Astrometry for Exoplanets

Validating the Orbital Periods of the Coolest TESS Exoplanet Candidates

The Search For The Inbetweeners: How Packed Are TESS Planetary Systems?

Material Cycling Across Earth’s Spheres And Triggers Of Cambrian Explosion: A Tectonic Perspective

Where Does Earth’s Nitrogen Go? Two Atoms Offer A Clue

Exotic Methanol Discovered In Planet-Building Zones

More Than One Thousand TESS Planets

First Detection Of Variable Water Clouds Outside Of Our Solar System